IntroductionBrain ventricles are dilated with accumulation of excess cerebrospinal fluid in it, which can cause the pressure damage to the surrounding structures. This study aims to highlight the reference range values for lateral and third ventricles of brain for easy diagnosis and management of hydrocephalic patients. Material and methodsWe calculated the frontal horn ratio(FHR), bi- caudate ratio(BCR), Evan’s ratio(ER), cella media ratio(CMR), bi-frontal index(BFI), bi- occipital index(BOI), third ventricle width(TVW), third ventricle sylvian fissure ratio index (TSFI), and third ventricle ratio (TVR) in 120 apparently normal CT-Head images and forty hydrocephalic images by taking linear measurements withdicom image software. Descriptive statistics –mean, standard deviation, standard error, 95% confidence interval were calculated for each parameter. Independent student t- test, age regression analysis, and Spearman’s rank correlation coefficient were applied accordingly. ResultsBCR, ER, TSFI showed significant correlation with the age and anteroposterior diameter of brain. BCR and TVW were significantly higher in males. In normal images, 95% confidence limits for FHR [0.295-0.309], TVW [6.104–6.92], TSFI [0.538–0.558] were found. The mean FHR and TVR in hydrocephalic patients were 0.42 and 0.072. DiscussionSince Frontal horn ratio and Third ventricle ratio do not depend upon the age, sex and size of brain, these two parameters can be used as the screening and monitoring tools in patients with hydrocephalus.